If you are a relative or someone you know is a relative of Gladys Pete you should take a DNA test and upload to as many sites as possible. While DNA is not 100% foolproof, it can confirm relationships and ancestors. Depending on how far back in time you're looking to go, it's important to remember that with each generation you inherit half of the previous generation's DNA, so once you hit 7-9 generations, DNA proof becomes challenging.
I try to triangulate these types of mysteries with both DNA and traditional records.
It sounds like you have a great research question, now you can formulate a plan!